GENUS SOLANXIM. 883 



With sclemte, in most grains, the qiiailrants arc very well defined, irregular in shape, and unequal 

 in size. The colors are quite pure. In those grains which show polarization colors the quadrants 

 are not well defined, the yellow quadrants are very light with greenish streaks, and the blue quad- 

 rants are almost yellow. 



Iodine Keactions. With 0.25 per cent Lugol's solution the grains are colored at once very 

 deeply a blue-violet; with 0.125 per cent solution they color lightly at once and the color deepens 

 quickly. After heating in water until all the grains are completely gelatinized, the solution is colored 

 fairly deeply, and most of the grains very deeply on the addition of iodme. After boiling for 2 

 minutes, the solution is colored very deeply and the grain-residues very lightly. With an excess of 

 iodine the capsules take on a violet color. Many of the grains are more or less disintegrated. 



Staining Reactions. With gentian violet the staining begins immediately and in 30 minutes 

 the color is very deep, in some grains much deeper than in others. 



With safranin staining begins immediately and in 30 minutes the color is a very deep rose. 

 The grains appear to be uniformly colored. 



Temperature Reaction. The temperature of gelatinization is 65 to 67 C, mean 66. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins in 5 minutes. Almost 

 all the grains are gelatinized in 15 mmutes and all in 30 minutes. The hilum becomes prominent 

 as a dark spot or bubble, but the lamellae are invisible. A light space may be seen extending from 

 the hilum and opening out fan-wise at the margin. The margin becomes dark at the distal end at 

 several points at which protrusion begins, the separate points soon becoming joined; or the reaction 

 may begin at the proximal end, or at both ends, from which the reaction progresses over the grain 

 and the grain swells imtil a large, gelatinized mass is formed which is composed of a dark, mar- 

 ginal ring surrounding a large, lighter, inner portion. (See plate 87, figs. 517 and 518.) 



Reaction with chromic acid begins in 30 seconds and is over in 6 minutes. Both hilum and 

 lamella; are prominent. The hilum begins to swell and a number of irregular cracks or fissures 

 appear in the central part of the grain, which run transversely or diagonally and widen out as the 

 grain swells. The hilum continues to swell and the more resistant portions of the grain form a 

 double ring whose inner portion is radially striated, while the outer shows very distinct alternate 

 light and dark concentric rings. The inner substance of the grain collects at the distal end, where 

 it forms a granular mass. The grain continues to swell, especially at the proximal end, until it is 

 about five times the normal size. Invagination occurs, usually only at the proximal, sometimes also 

 at the distal end. The marginal part which has been growing thinner and clearer dissolves at the 

 proximal end, and also sometimes at the other end, and the inner, granular starch flows out and is 

 dissolved. Solution of other parts of the margin follows slowly. 



The reaction with pyrogallic acid begins in 3 minutes. Almost all the grains are affected and 

 nearly all are completely gelatinized in 25 minutes. After this time there is no reaction. The hilum 

 and lamellae are more prominent than usual. The hilum swells slightly and a diagonal fissure 

 extends down the grain on each side, outlining a very narrow iimer portion. As the hilum con- 

 tinues to swell, this inner portion is split by a number of irregular fissures, the portions of grain- 

 substance often adhering for some time. These parts are transformed into a granular mass at the 

 base of the grain. The more resistant marginal portion of the grain forms a thick ring, which shows 

 distinct, alternate refractive and non-refractive concentric bands, but is not distinctly striated. 

 This ring becomes invaginated at the base as the grain continues to swell, and the marginal band 

 clears verj' gradually until a large gelatinous mass is formed, which is rounded at the proximal end 

 and folded and lobulated at the distal end. 



The reaction with ferric chloride begins in 2J^ minutes and is completed in 23 minutes. The 

 hilum is prominent, but the lamellae are obscured. The margin darkens and becomes clearer, and 

 is fissured at the distal or proximal end, from which fissures a gelatinous substance protrudes. Sud- 

 denly the hilum swells and invagination occurs from the distal end of the grain almost up to the 

 other end, causing the grain to show a double row of striated, banded material on either side of a 

 clear space. This banded material gradually clears and becomes thinner, and there is left a very 

 large, rather shapeless, gelatinous mass. Near the edge and outside of the cover-slip the grains 

 do not react so quickly. 



Reaction with Purdij's solution begins in 20 seconds and is over in 45 seconds. Both hilum and 

 lamella; become very prominent. The hilum swells slightly and a fine diagonal fissure extends 

 down on each side from the hilum to the distal end, and outlines a very narrow, iimer portion of 



